For the love of God, don’t do that. Passing passwords in URLs is a tremendously unwise practice – the URLs end up in browser history, server logs, proxy logs, etc. If this is for automation, consider POST with the password in the body, or better yet, API tokens.

Do this only if you really know what you are doing and understand the security implications. I would not recommend this for production systems, but some people ask for it, so…

It is possible to sign in to Zabbix using password using URL parameters in clear text.

Here is the format:
http://test.zbx.cz/zabbix/index.php?name=your_username&password=your_password&enter=Sign%20in&request=desired_page

You can URL encode the special characters, but don’t have to.

https://test.zbx.cz/zabbix.php?action=dashboard.view&dashboardid=1

https://test.zbx.cz/index.php?name=bob&password=censoredpassword&enter=Sign%20in&request=zabbix.php?action=dashboard.view&dashboardid=1

For example, the special characters in the password need to be URL encoded as follows:
https://test.zbx.cz/index.php?name=bob&password=V%2BPj%3C~aAYs%3E5%22Lw9tKeU%21%7B%29hRB%7D%40%3FErKa2nd3TDX7%2AQu-%5D4z%5B&enter=Sign%20in&request=zabbix.php?action=dashboard.view&dashboardid=1

http://test.zbx.cz/zabbix/index.php?name=admin&password=Password&enter=Sign%20in&request=zabbix.php?action=map.view&sysmapid=3

Needless to say, this would not work with MFA.